In: Statistics and Probability
Emerging evidence suggests that younger maternal age may increase the rate of stroke within 6 weeks of delivery. Let’s use the following HYPOTHETICAL dataset to explore this association (Table 1). Women were classified as aged 16-19 years, 20-34 or 35-44 at the time of delivery. Within each maternal age category, person-time accrued until a woman either had a stroke within 6 weeks of delivery, was lost to follow-up or died of other causes, or was no longer at risk (beyond 6 weeks post-delivery).
Table 1: Association between maternal age and stroke within 6 weeks of delivery
Aged 16-19 |
Aged 20-34 |
Aged 35-44 |
Total |
|
Stroke |
23 |
281 |
45 |
349 |
No Stroke |
229,692 |
3,097,513 |
539,844 |
3,867,049 |
Total Person-Weeks |
1,378,159 |
18,585,546 |
3,239,006 |
23,202,711 |
a. Calculate the incidence rate ratio for the association between maternal age 16-19, relative to maternal age 35-44, and stroke within 6 weeks of delivery. Round to two decimal places. (3 points)
b. Calculate the excess incidence rate ratio for the association between maternal age 20-34, relative to maternal age 35-44, and stroke within 6 weeks of delivery. Round to two decimal places. (3.5 points)